1. determine if the following are probability distributions (if no, state why). a. x 3 6 9 12 15 p(x) 4/9 2/9 4/9 1/9 1/9a. yes, the values of X are all positiveb. yes, the probbabilities associated with each X are all positive and they all add up to 1c. no, the values of X do not start at 1 and the probabilities do not add up to 1d. no, the probabilities do not add uo to 1